Method for optimized prediction of the postoperative anatomical position of an intraocular lens implanted in a pseudopakic eye

ABSTRACT

Postoperative lens position is predicted on the basis of known measured values, such as the corneal thickness, the depth of the anterior chamber, the eye length, and the distances of the capsular bag equator and/or of the lens haptic from the anterior surface of the lens. In addition, the calculation also takes into account the attitude of the intraocular lens, for which purpose additional parameters of the pseudophakic eye are used that have not previously been taken into consideration.; The proposed method is suitable for a more exact prediction of the strength and nature of an intraocular lens to be implanted in a pseudophakic eye in the context of cataract surgery or of a refractive intervention. The method is based on the use of suitable calculation methods, e.g. geometric optical formulae, or of ray tracing.

RELATED APPLICATIONS

The present application is a National Phase entry of PCT Application No.PCT/EP2012/063190, filed Jul. 5, 2012, which claims priority from DEApplication No. 10 2011 106 714.4, filed Jul. 6, 2011, whichapplications are hereby incorporated by reference herein in theirentirety.

FIELD OF THE INVENTION

The present invention relates to a method for the preoperative selectionof an intraocular lens to be implanted in an eye. In doing so, theresults of the refractive intervention on the eye are to be optimized byapplication of a prediction of the postoperative, anatomical position ofthe implanted intraocular lens.

BACKGROUND

According to known prior art, intraocular lens (IOLs) are selected andadjusted based on the measured and/or estimated measurements, whereinonly individual parameters in the form of individual measurement valuesor as a mean value over specified patient groups are taken intoconsideration.

In this regard, the selection and adjustment of the optimal IOL takesplace solely according their features, such as type, refractive power,asphericity, and multifocality. Taking into account possibledependencies on specific accompanying circumstances of the treatment,such as characteristics of the patients, diagnoses, surgical procedures,and similar, occurs just as infrequently as the use of statisticaldistribution for the parameters.

Selecting the suitable intraocular lens for a patient is theresponsibility of the cataract surgeon. In this regard, the surgeon musttake into consideration many factors. First, depending on the individualbiometric parameters of the eye, the suitable calculation method of theIOL refractive power should be selected. To do so, generally forextraordinarily long, normal, or extraordinarily short eyes, variousmore or less suited formulas are used for calculation purposes. In thesimplest situation, their input parameters are based on keratometry andaxis lengths of the eye, wherein the formulas, due to their simplifiedmodel assumptions, also contain an empirically determined correctionfactor, such as the so-called A constant, for example.

The currently most widespread calculation methods are the so-called IOLformulas, e.g., according to Haigis, Holladay, Hoffer, Olsen, Shammas,or SRK. Accordingly, refraction D (output/evaluation parameter) of thepatient is calculated after inserting the IOL by

D=D IOL −f(K, AL, VKT, A)   (1)

wherein f( ) is a conventionally known IOL formula

-   -   DIOL is the refractive power of the IOL,    -   K is the measured keratometry value,    -   AL is the measured axis length of the eye,    -   VKT is the measured depth of the anterior chamber and    -   A is an IOL-type-dependent constant input value.

The various calculation methods (biometry formulas) generally usevarious IOL-type-dependent constants (i.e., IOL constants). An Aconstant is used in the SRK formula for example.

For selecting the IOL, the physician sets a target refraction(D=Dtarget). For optimization purposes, the physician calculates therefraction (1) according to various IOLs by varying DIOL and A. In manycases, the physician uses IOLs of the same type, so that no variation inA results, and the optimization boils down to a formula calculationaccording to DIOL=Dtarget+f(K, AL, VKT, A). If emmetropia is theobjective, this results in the traditional formula calculation of theIOL according to DIOL=f(K, AL, VKT, A).

The constant A in the formulas is determined empirically via a patientgroup to adapt the formula values to the actually resulting optimalrefraction values. However, this adaptation only ensures that the meanvalue of the refraction values agrees with the formula over the testgroup.

To minimize systematic errors, currently other approaches are beingselected according to prior art.

For example, a series of physicians uses a different A constant for eachethnic group among their patients. In this way, errors can besystematically reduced and, to the extent the statistical scatter in therespective group is lower, so can the statistical errors.

Depending on specified starting conditions, such as patients with longaxis lengths or with prior refractive corneal surgery, other physiciansuse various biometry formulas that are better adapted to the respectiverequirements, or that presuppose the measurement of additionalparameters, such as anterior chamber depths or lens thickness. Here,too, systematic errors in particular are decreased, wherein however, thestatistical errors can increase partially due to the additionallymeasured parameters.

Presupposing or predicting the postoperative effective lens position(ELP), i.e., the “effective” position of the implanted intraocular lensin the eye, plays a major role. Various formulas pertain to determiningthe postoperative ELP of various assumptions, based on diverse biometricparameters of the eye. In the simplest case, these are: keratometry andaxis length of the eye. Fourth-generation formulas, as they are called,use up to six parameters for predicting the ELP, such as: axis length,anterior chamber depth, keratometry, lens thickness, limbus diameter,and age of the patient. Due to the simplified model assumptions of theeye, as well as the “empirical” nature of the many formulas, i.e.,optimization of the formula results via constants, “virtual” valuesresult for the calculated ELP, so that the ELP required for an optimizedresult does not generally correspond to the actual anatomical lensposition in the eye. The reason for this is that due to thepostoperative refraction results and the resulting average errorcorrection (e.g., through the A constant), only the predicted ELP canchange because all other parameters were measured. Optimization viaconstants does not take into account that other preoperatively measuredparameters could have changed postoperatively in addition to theexpected refraction result.

Another method to predict the ELP is based on the principle ofdetermining the capsular bag equator and is described in U.S. Pat. No.5,968,095 A. In doing so, the distance of the lens haptic to theanterior surface of individual IOL designs is taken into account. Theposition of the capsular bag equator can thus be determined in variousways. With this method, one can theoretically achieve a prediction ofthe ELP that is independent of the individual IOL design.

In contrast to the postoperative effective lens position (ELP), whichdue to the simplified model assumption of the eye as well as empiricalformulas does not generally correspond to the actual anatomical lensposition, the anatomical postoperative lens position defines the actual,i.e., real, postoperative position of the intraocular lens to beimplanted.

The term “haptic” refers to the support structure existing for fixingthe intraocular lens in the eye. The haptics are arranged peripherallyto the actual optic lens and may be constructed in various shapes, suchas brackets, plates, or straps.

In the known IOL design-dependent or independent methods according toprior art for predicting or determining the postoperative ELP, adisadvantageous effect is that none of the known methods can do withoutempirical correction factors. One reason for this are individualpostoperative healing processes that usually last over a period ofseveral weeks, which is not taken into account in the methods known todate. Another reason may be seen in that despite diverse methods, onlyan insufficient number of parameters relevant for determining the ELP istaken into account in the prediction.

Another problem lies in the optimization method of the formulaapproaches. Improving the postoperative refraction results byapplication of the constant procedure takes into consideration allerrors occurring in cataract surgery. These are errors in themeasurement procedures, errors in the IOL calculation, and unexpectedevents during the implantation and healing processes. However,optimizing the results solely by use of postoperative refractionexcludes individual error sources from being taken into account.

SUMMARY OF THE INVENTION

The invention is to eliminate the disadvantages of the solutions knownfrom prior art and to optimize the prediction of the postoperative lensposition of an intraocular lens to be implanted in a pseudophakic eye.

This object is achieved with the method according to the invention foroptimizing the prediction regarding the postoperative lens position ofan intraocular lens to be implanted in a pseudophakic eye, for whichsaid lens calculations are performed by known measurements, such ascorneal thickness, anterior chamber depth, eye length, as well as thedistance of the capsular bag equator and lens haptics to the anteriorsurface of the lens, in that besides the anatomical, postoperativeposition of the intraocular lens to be implanted, their position is alsoincluded in the calculation, for which additional parameters not takeninto account before of the pseudophakic eye, such as the diameter of thecapsular bag equator and capsulorhexis, the preoperative decentrationand tilting of the eye lens, the center of the pupil region, as well asthe haptic diameter and the haptic-type of the intraocular lens used aretaken into account.

The term “capsulorhexis” refers to the disk-shaped opening of theanterior surface of the capsular bag and represents an elegant methodwithin the scope of a cataract treatment, in which the capsular bag isperforated and opened by a tearing maneuver.

The proposed method according to the invention is suited for a moreexact prediction of the strength and type of an intraocular lens to beimplanted in a pseudophakic eye within the scope of a surgical cataractor refractive intervention. In doing so, the method is based on the useof suitable calculation methods, e.g., geometric-optic formulas or raytracing, in which, besides known measurement values, pseudophakic eyeparameters not taken into account to date are also used.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described hereafter in greater detailed usingembodiments.

FIG. 1 depicts a schematic diagram of the anterior eye segments with thecorresponding parameters.

FIG. 2 depicts a sample representation of the dependency of theanatomical lens position on the ratio of the capsular bag diameter tocapsulorhexis.

FIG. 3 depicts a sample representation of the dependency of theanatomical lens position on the ratio of the capsular bag diameter tothe haptic.

DETAILED DESCRIPTION

In the method according to the invention for optimally predicting thepostoperative lens position (LP_(an-post)) of an intraocular lens (L) tobe implanted in a pseudophakic eye by application of known measurementvalues, such as the corneal thickness (HHD), the anterior chamber depth(VKT), the eye length (AL) as well as the distances of the capsular bagequator (KSA) and the lens haptics (LH) of the anterior surface of thelens (LV), besides the anatomical, postoperative position (LP_(an-post))of the intraocular lens (L) to be implanted, their position(LL_(an-post)) is also included in the calculation, for which purposeadditional, not yet considered parameters of the pseudophakic eye areused. As additional parameters of the pseudophakic eye, the diameter ofthe capsular bag and capsulorhexis, the preoperative decentration, andtilting of the eye lens, the center of the pupil region (PBM), as wellas the haptic diameter (LHD) and the haptic-type (LHT) of the usedintraocular lens (L) are taken into account.

To this end, FIG. 1 depicts a schematic diagram of the anterior eyesegments with their components and the corresponding parameters. Anoverview of the abbreviations used is provided in the list of referencesigns.

In a first embodiment of the method according to the invention, thepostoperative, anatomical lens position LP_(an-post) results from thefollowing formula:

LP _(an-post) =VKT−HHD+A1_(KSA-LV)   (2)

in which

-   -   VKT characterizes the anterior chamber    -   HHD characterizes the corneal thickness and    -   A1 _(KSA-LV) characterizes the distance between the capsular bag        equator and the anterior surface of the lens and distance A1        _(KSA-LV) stems from the following formula:

A1_(KSA-LV)=(LD/3−A2_(LH-LV))+f (V1_(KSD-KHD))+f (V2_(KSD-LHD))+f (LHT)  (3)

in which

-   -   LD characterizes the lens thickness,    -   A2 _(LH-LV) characterizes the distance between lens haptics and        the anterior surface of the lens    -   f(V1 _(KSD-KHD)) characterizes a function of the ratio of the        capsule sack diameter to the capsulorhexis,    -   f(V2 _(KSD-KHD)) characterizes a function of the ratio of the        capsular bag diameter to the lens haptic and    -   f(LHT) characterizes a function of the lens haptic-type

Accordingly, the ratios V1 _(KSD-KHD) and V2 _(KSD-LHD), as well as theinfluence of the lens haptic-type LHT used are determined empirically instudies and quantified as a function.

Accordingly, it is possible that the functions f (V1 _(KSD-KHD)) and f(V2 _(KSD-LHD)) are determined for individual or also for a number ofdifferent lens designs.

The ratio of the capsular bag to capsulorhexis diameters results herebyas function f(V1 _(KSD-KHD)) from the following formula:

f (V _(KSD-KHD))=KHD/KSD·KSD _(norm) /KHD _(norm)   (4)

in which

-   -   KHD characterizes the diameter of the capsulorhexis,    -   KSD characterizes the diameter of the capsular bag,    -   KSD_(norm) characterizes the individual mean diameter of the        capsular bag and    -   KHD_(norm) characterizes the capsulorhexis diameter empirically        determined as a function of various parameters        wherein for example the pathology, ethnic origin, sex, and age        can be taken into account as an empirical scaling function.

To this end, FIG. 2 depicts a sample representation of the dependency ofthe anatomical lens position through the ratio of the capsular bagdiameter to the capsulorhexis diameter. This dependency is to bedetermined empirically in studies and quantified as a function, wherebythe resulting function can change according to the selected scalingfunction, e.g., the pathology, ethnic origin, sex, age or similar.Accordingly, it is also possible that no function can be quantified.

The representation for example purposes shows distance A1 _(KSA-LV)resulting as a function of the ratio of the capsular bag diameter to thecapsulorhexis diameter, said distance included as a correction value viaformula (3) in formula (2), from which an optimized value thus resultsfor the postoperative, anatomical lens position LP_(an-post).

Correspondingly, the ratio of the capsular bag diameter to the lenshaptic diameter as a function f (V2 _(KSD-LHD)) results from thefollowing formula:

f (V2_(KSD-LHD))=LHD/KSD·KSD _(norm) /LHD   (5)

in which:

-   -   LHD characterizes the specific diameter of the lens haptic,    -   KSD characterizes the diameter of the capsular bag and    -   KSD_(norm) characterizes an individual mean diameter of the        capsular bag        wherein in turn for example the pathology, ethnic origin, sex,        and age can be taken into account as empirical scaling        functions.

To this end, FIG. 3 depicts a sample representation of the dependency ofthe anatomic lens position on the ratio of the capsular bag diameter tothe haptic diameter. This dependency is also to be determinedempirically in studies and quantified as a function, wherein theresulting function can in turn change depending on the selected scalingfunction, e.g., the pathology, ethnic origin, sex, age or similar. Heretoo, it is possible that no function can be quantified.

The representation for example purposes shows distance Al_(KSA-LV)resulting as a function of the ratio of the capsular bag diameter to thehaptic diameter, said distance included as a correction value viaformula (3) in formula (2), from which an optimized value thus resultsfor the postoperative, anatomical lens position LP_(an-post).

If in contrast to the representations depicted in FIGS. 2 and 3, nodependencies can be discerned in the ratios of the capsular bag diameterto the capsulorhexis diameter V1 _(KSD-KHD) or capsular bag diameter tolens haptic diameter V2 _(KSD-LHD), then f(V1 _(KSD-KHD)) and f (V2_(KSD-LHD)) each take on the value of zero.

In a second embodiment of the method according to the invention, thepostoperative, anatomic lens position (LL_(an-post)) can be described bythe following three parameters:

-   -   LDZ—horizontal and vertical decentration of the lens,    -   LVK—horizontal and vertical tilting of the lens and    -   PBM—center of the pupil region that can be used in the        calculation.

Accordingly, the horizontal and vertical decentration LDZ of the lensresults from the following formula:

LDZ=LDZ _(eye) ×f(LDZ _(eye))   (6)

in which

-   -   LDZ_(eye) characterizes the horizontal and vertical decentration        of the actual eye lens and    -   f(LDZ_(eye)) characterizes an empirical function of the        decentration of the actual eye lens        wherein for example the pathology, the ethnic origin, sex, and        age can be taken into account as empirical scaling functions.

Correspondingly, the horizontal and vertical tilting LVK of the lensresults from the following formula:

LVK=LVK _(eye) ×f(LVK _(eye))   (7)

in which

-   -   LVK_(eye) characterizes the horizontal and vertical tilting of        the actual eye lens and    -   f(LVK_(eye)) characterizes an empirical function of the tilting        of the decentration of the actual eye lens        wherein in turn the pathology, ethnic origin, sex, and age for        example can be taken into account as empirical scaling        functions.

The center of pupil region PBM that can be used for the calculationstems in contrast from the following formula:

PBM=HHV−PDZ−LDZ   (8)

in which

-   -   HHV characterizes the corneal vertex,    -   PDZ characterizes the horizontal and vertical decentration of        the pupil and    -   LDZ characterizes the horizontal and vertical decentration of        the lens

Accordingly, it is here also possible that the empirically determinedscaling functions are determined for individual or also a number ofdifferent lens designs.

According to a third advantageous embodiment of the method according tothe invention, it is hereby possible that the postoperative, anatomiclens position LL_(an-post) or the center of the pupil region PBM usablefor the calculation can be determined on various pupil apertures, suchas photopic, scotopic, or mesopic vision.

According to another example embodiment of the method according to theinvention for optimally predicting the anatomical, postoperativeposition LP_(an-post) of an intraocular lens to be implanted in apseudophakic eye, calculation methods, such as geometric-opticalformulas or ray tracing, can be used to calculate the intraocular lens Lto be implanted.

The method according to the invention is based on the assumption thatthe postoperative positioning or displacement of the (IOL) lens isdetermined within the scope of the healing process by the “fit-abilityof the preoperative capsular bag to the size and shape of the (IOL) lenshaptic as well as the capsulorhexis.

By the possible inclusion of additional parameters that describe theinsertion of the lens in the capsular bag, a more exact prediction ofthe anatomical, postoperative lens position is made possible.

The parameters listed in FIG. 1 of the reference sign list can bedirectly determined only to a partial degree using today's conventionaltechnology. For example, the capsular bag diameter and the distance ofthe capsular bag equator to the cornea cannot be determined by opticalmeans. For that reason, a component of the solution is the use of animage of the eye section that comprises at least the anterior cornealsurface all the way to the rear surface of the capsular bag. Such animage can be obtained by means of Scheimpflug photography or OCTtechnology. From the parts, made visible in this image of the posteriorand anterior lens surface and suitable software algorithms, the imagecan be completed to the capsular bag equator so that the distance of thecornea to the capsular bag equator, as well as the capsular bag diametercan be determined.

In addition, it shall be assumed that the natural human lens isgenerally tilted and decentered due to physiological reasons. For thatreason, an additional assumption underlying the solution is that theimplanted intraocular lens is also positioned in the eye in a tilted anddecentered manner and that the pre- and postoperative decentering andtilting correlate.

With the solution according to the invention, a method for predictingthe anatomical, postoperative position of an intraocular lens to beimplanted in a pseudophakic eye is provided, with which, in addition tothe lens position, the lens attitude of the intraocular lens to beimplanted can be predicted in a more optimized and thus more precisemanner.

Predicting or optimizing the prediction of the anatomical, postoperativelens position is achieved by application of parameters not taken intoaccount to date and is thus independent of the postoperative refractionresult. Erroneous postoperative refraction results, which are not causedby an erroneous anatomical lens position, are not taken into account inpredicting the anatomical lens position.

For the prediction, not only are the capsular bag equator and thedistance of the lens haptic to the anterior surface of the lens takeinto account in the prediction, but also the capsular bag diameter, thecapsulorhexis diameter, the corneal thickness, the preoperative lensdecentration, and lens tilting, as well as the haptic diameter andhaptic type of the (IOL) lens.

By application of the method according to the invention, the exactprediction of the anatomical, postoperative position of the intraocularlens to be implanted is possible for each individual eye.

REFERENCE LIST

-   L (IOL) lens-   LP_(an-post) anatomical, postoperative position of the (IOL) lens-   LL_(an-post) anatomical, postoperative attitude of the (IOL) lens-   HHD corneal thickness-   HHV corneal vertex-   VKT anterior chamber depth-   KS capsular bag-   KSA capsular bag equator-   KSD capsular bag diameter-   KSD_(norm) mean diameter of capsular bag-   KH capsulorhexis-   KHD capsulorhexis diameter-   KHD_(norm) empirically determined diameter of capsulorhexis-   LD lens thickness (of the IOL)-   LH lens haptic (of the IOL)-   LHD lens haptic diameter-   LHT lens haptic-type-   LV anterior surface of lens (IOL)-   A1 _(KSA-LV) distance A1 between the capsular bag equator and the    anterior surface of the lens-   A2 _(LH-LV) distance A2 between the lens haptic and the anterior    surface of the lens-   V1 _(KSA-KHD) ratio of the capsular bag and capsulorhexis diameters-   V2 _(KSD-LHD) ratio of the capsular bag to the lens haptic-   LDZ horizontal and vertical decentration of the (IOL) lens-   LDZ_(eye) horizontal and vertical decentration of the actual eye    lens-   LVK horizontal and vertical tilting of the (IOL) lens-   LVK_(eye) horizontal and vertical tilting of the actual eye lens-   PD pupil diameter-   PDZ horizontal and vertical decentration of the pupil-   PBM center of the pupil region that can be used for the calculation

1-13. (canceled)
 14. A method for optimized prediction of postoperativelens position (LP_(post)) of an intraocular lens to be implanted in apseudophakic eye, comprising: using known measurement values, includingcorneal thickness (HHD), anterior chamber depth (VKT), eye length (AL)as well as the distance of the capsular bag equator (KSA) or lens haptic(LH) to the anterior surface of the lens (LV) for calculation; andincluding in the calculation an anatomical, postoperative position(LP_(an-post)) of the intraocular lens (L) to be implanted and anorientation (LL_(an-post)) of the intraocular lens and additionalparameters not yet taken into account of the pseudophakic eye.
 15. Themethod according to claim 14, further comprising taking into account atleast one factor selected from a group consisting of a diameter of thecapsular bag and a diameter of a capsulorhexis, a preoperativedecentration and a tilting of the eye lens, a center of the pupil range(PBM), a haptic diameter (LHD) and a haptic type (LHT) of theintraocular lens (L) used.
 16. The method according to claim 14, furthercomprising determining a postoperative, anatomical lens position(LP_(an-post)) from formula (2):LP _(an-post) =VKT−HHD+A1_(KSA-LV) VKT represents the anterior chamberdepth in which HHD represents the corneal thickness and A1 _(KSA-LV)represents the distance between the capsular bag equator and theanterior surface of the lens and determining distance A1 _(KSA-LV) fromformula (3):A1_(KSA-LV)=(LD/3−A2_(LH-LV))+f (V1_(KSD-KHD))+f (V2_(KSD-LHD))+f (LHT)  (3) in which LD represents the lens thickness, A2 _(LH) _(—) _(LV)represents the distance between the lens haptic and the anterior surfaceof the lens, f(V1 _(KSD-KHD)) represents a function of the ratio of thecapsular bag to capsulorhexis diameters f (V2 _(KSD-KHD)) represents afunction of the ration of the capsular bag to the lens haptic diameter sand f (LHT) represents a function of lens haptic type.
 17. The methodaccording to claim 15 further comprising determining a postoperative,anatomical lens position (LP_(an-post)) from formula (2):LP _(an-post) =VKT−HHD+A1_(KSA-LV)   (2) in which VKT represents theanterior chamber depth HHD represents the corneal thickness and A1_(KSA-LV) represents the distance between the capsular bag equator andthe anterior surface of the lens
 18. The method according to claim 16,further comprising empirically determining the ratios V1 _(KSD-KHD) andV2 _(KSD-LHD), and the influence of the lens haptics-type LHT in studiesand quantifying the ratios V1 _(KSD-KHD) and V2 _(KSD-LHD), and aninfluence of the lens haptics-type LHT as functions.
 19. The methodaccording to claim 17, further comprising empirically determining theratios V1 _(KSD-KHD) and V2 _(KSD-LHD), and the influence of the lenshaptics-type LHT in studies and quantifying the ratios V1 _(KSD-KHD) andV2 _(KSD-LHD), and an influence of the lens haptics-type LHT asfunctions.
 20. The method according to claim 18, further comprisingdetermining the functions f (V1 _(KSD-KHD)) and f (V2 _(KSD-LHD)) forindividual lens designs or for a number of different lens designs. 21.The method according to claim 16, wherein f (V1 _(KSD-KHD)) results as afunction from the ratio of the capsular bag to capsulorhexis diametersfrom formula (4):f (V1_(KSD-KHD))=KHD/KSD·KSD _(norm) /KHD _(norm)   (4) in which KHDrepresents the diameter of the capsulorhexis KSD represents the diameterof the capsular bag KSD_(norm) represents an individual mean diameter ofthe capsular bag KHD_(norm) represents an empirically determineddiameter of the capsulorhexis as a function of various parameterswherein at least one of pathology, ethnic origin, sex, and age are takeninto account as empirical scaling functions.
 22. The method according toclaim 18, wherein f (V1 _(KSD-KHD)) results as a function from the ratioof the capsular bag to capsulorhexis diameters from formula (4):f (V1_(KSD-KHD))=KHD/KSD·KSD _(norm) /KHD _(norm)   (4) in which KHDrepresents the diameter of the capsulorhexis KSD represents the diameterof the capsular bag KSD_(norm) represents an individual mean diameter ofthe capsular bag KHD_(norm) represents an empirically determineddiameter of the capsulorhexis as a function of various parameterswherein at least one of pathology, ethnic origin, sex, and age are takeninto account as empirical scaling functions.
 23. The method according toat least one of the claims 18, wherein f (V2 _(KSD-LHD)) results as afunction from the ratio of the diameter of the capsular bag to the lenshaptic from formula (5):f (V2_(KSD-LHD))=LHD/KSD·KSD_(norm) /LHD   (5) in which LHDcharacterizes the specific diameter of the lens haptic KSD characterizesthe diameter of the capsular bag and KSD_(norm) characterizes anindividual mean diameter of the capsular bag wherein at least one ofpathology, ethnic origin, sex, and age are taken into account asempirical scaling functions.
 24. The method according to claim 14,further comprising describing the anatomical, postoperative lensorientation (LL_(an-post)) by the following three parameters:LDZ—horizontal and vertical decentration of the lens, LVK—horizontal andvertical tilting of the lens, and PBM—center of the pupil region thatcan be used in the calculation.
 25. The method according to claim 15,further comprising describing the anatomical, postoperative lensorientation (LL_(an-post)) by the following three parameters:LDZ—horizontal and vertical decentration of the lens, LVK—horizontal andvertical tilting of the lens, and PBM—center of the pupil region thatcan be used in the calculation.
 26. The method according to claim 14,further comprising determining the horizontal and vertical decentrationLDZ of the lens results from formula (6):LDZ=LDZ _(eye) ×f(LDZ _(eye))   (6) in which LDZ_(eye) represents thehorizontal and vertical decentration of the actual eye lens andf(LDZ_(eye)) represents an empirical function of the decentration of theactual eye lens wherein at least one of pathology, ethnic origin, sex,and age are taken into account as empirical scaling functions.
 27. Themethod according to claim 15, further comprising determining thehorizontal and vertical decentration LDZ of the lens results fromformula (6):LDZ=LDZ _(eye) ×f(LDZ _(eye))   (6) in which LDZ_(eye) represents thehorizontal and vertical decentration of the actual eye lens andf(LDZ_(eye)) represents an empirical function of the decentration of theactual eye lens wherein at least one of pathology, ethnic origin, sex,and age are taken into account as empirical scaling functions.
 28. Themethod according to claim 24, further comprising determining thehorizontal and vertical decentration LDZ of the lens results fromformula (6):LDZ=LDZ _(eye) ×f(LDZ _(eye))   (6) in which LDZ_(eye) represents thehorizontal and vertical decentration of the actual eye lens andf(LDZ_(eye)) represents an empirical function of the decentration of theactual eye lens wherein at least one of pathology, ethnic origin, sex,and age are taken into account as empirical scaling functions.
 29. Themethod according to claim 14, further comprising determining thehorizontal and vertical tilting LVK of the lens results from formula(7):LVK=LVK _(eye) ×f(LVK _(eye))   (7) whereby LVK_(eye) represents thehorizontal and vertical tilting of the actual eye lens andf(LVL_(eye))represents an empirical function of the tilting of the decentration ofthe actual eye lens wherein at least one of pathology, ethnic origin,sex, and age are taken into account as empirical scaling functions. 30.The method according to claim 15, further comprising determining thehorizontal and vertical tilting LVK of the lens results from formula(7):LVK=LVK _(eye) ×f(LVK _(eye))   (7) whereby LVK_(eye) represents thehorizontal and vertical tilting of the actual eye lens andf(LVK_(eye))represents an empirical function of the tilting of the decentration ofthe actual eye lens wherein at least one of pathology, ethnic origin,sex, and age are taken into account as empirical scaling functions. 31.The method according to claim 24, further comprising determining thehorizontal and vertical tilting LVK of the lens results from formula(7):LVK=LVK _(eye) ×f(LVK _(eye))   (7) whereby LVK_(eye) represents thehorizontal and vertical tilting of the actual eye lens andf(LVK_(eye))represents an empirical function of the tilting of the decentration ofthe actual eye lens wherein at least one of pathology, ethnic origin,sex, and age are taken into account as empirical scaling functions. 32.The method according to claim 14, further comprising determining thecenter of the pupil region PBM that is used for the calculation fromformula (8):PBM=HHV−PDZ−LDZ   (8) in which HHV represents the corneal vertex, PDZrepresents the horizontal and vertical decentration of the pupil and LDZrepresents the horizontal and vertical decentration of the lens.
 33. Themethod according to claim 15, further comprising determining the centerof the pupil region PBM that is used for the calculation from formula(8):PBM=HHV−PDZ−LDZ   (8) in which HHV represents the corneal vertex, PDZrepresents the horizontal and vertical decentration of the pupil and LDZrepresents the horizontal and vertical decentration of the lens.
 34. Themethod according to claim 24, further comprising determining the centerof the pupil region PBM that is used for the calculation from formula(8):PBM=HHV−PDZ−LDZ   (8) in which HHV represents the corneal vertex, PDZrepresents the horizontal and vertical decentration of the pupil and LDZrepresents the horizontal and vertical decentration of the lens.
 35. Themethod according to claim 24, wherein the center of the pupil region PBMthat can be used for the calculation can refer to various pupilapertures, including for photopic, scotopic, or mesopic vision.
 36. Themethod according to claim 26, wherein the center of the pupil region PBMthat can be used for the calculation can refer to various pupilapertures, including for photopic, scotopic, or mesopic vision.
 37. Themethod according to claim 14, further comprising using geometric-opticalformulas or ray tracing to calculate the intraocular lens (L) to beimplanted in the pseudophakic eye.